Many devices have heretofore been proposed for securing a door in closed position and for retaining it in open position. For example, a door can be secured in closed position by a lock or sliding bolt. However, such devices do not serve to retain a door in open or partially open position. For the latter purpose it has been proposed to use a plunger or a pivoted brace mounted near the bottom of the door and engageable with the floor. However, such devices are not capable of securing a door in closed position in a positive manner. Morever, they have been inconvenient to operate and have not been found to be wholly effective in retaining a door in open or partially open position.